The rapid and accurate diagnosis of infection is critical for managing potential exposures to highly virulent pathogens, whether occurring from an act of bioterrorism or a natural event. Antibodies are very sensitive serum biomarkers that can be exploited to identify recent or past exposures to infectious agents, and antibody analysis methods are especially important for samples containing negligible amounts of detectable virus or genetic material from the pathogen. Commonly practiced methods for measuring antibody responses in the clinic are generally encumbered by a focus on single pathogens, several time-consuming performance steps, slow turn-around time for data acquisition, issues of specificity and sensitivity, and variable results. We propose to develop a simple microfluidic device that will integrate many complex tasks required for antibody- based diagnosis, from processing of finger-prick blood samples to identifying exposures to specific infectious agents, taking advantage of the unique physical properties of micro- and nanofluidics to enhance assay performance. Our studies will focus on point-of-care diagnosis of infections caused by two pathogen groups with the greatest potential impact on public health: arboviruses (Japanese Encephalitis, Chikungunya, Dengue, Yellow Fever and others) and filoviruses (Ebola, Marburg). We envision that the microarray format of the microfluidic device can be rapidly expanded to include tests for an extensive number of other biological agents. The collaborative team will consist of investigators from the Biosensor and Protein Microarray Laboratory from the Research Institute of Infectious Diseases, and the MicroElectroMechanical Systems (MEMS) and Microfluidics Laboratory of the University of Maryland. The project team includes unique expertise in infectious disease research, MEMS, microfluidic systems, and microarray-based technologies for the high-throughput detection of human antibody interactions with signature proteins of pathogens. Sera from clinical and veterinary cases of infection will be used for extensive evaluation of the device. Our approach will require only nanoliter quantities of serum for analysis and will lead to the development of a low cost, disposable device for rapid and sensitive detection of pre-symptomatic, symptomatic or convalescent biomarkers of infectious diseases.